Clogging due to air or pigment settling? - dotted nozzle tests and banding 9900

I have experienced some misbehaving nozzles in my nozzle tests…

Previously, I had shaken the cartridges in order to keep the pigments in suspension. I switched off the printer before taking each cartridge out, but for some reason I forgot to pop open the plugs at the top of the cartridges before shaking. I shook the cartridges by making the ink run from front to back of the cartridge, that is, by tilting the cartridge towards the front and towards the back across its length.

When I started printing, I realized there was some banding, and performed a few nozzle tests. I realized:

  • A very limited number of nozzles were not firing – when I printed several nozzle checks, with or without cleaning cycles, these non-firing nozzles changed of position on every test. I think these are called “Unstable nozzle out”…

  • Therefore, I realized some inks, particularly the shade 1, had all the nozzles printing, but the vast majority of them showed dotted lines rather than continuous lines… After a series of cleanings and power cleanings, the dotted lines were gradually transformed into continuous lines. On some other lighter ink shades, some nozzle lines turned into dotted, in a unstable way (jumping from one position to another in consecutive tests). I have to clarify that all nozzles were firing the whole length of the lines, but these were dotted (dots almost in contact, but dots) rather than perfectly continuous.

My questions are:

  • Nozzles that print dotted lines instead of a perfect continuous line could be said to be misfiring? Or that behavior can be assumed to be normal? Why only the very darkest shade is prone to print dotted lines in the nozzle test?

  • Which could be the reason for the unstable non-firing-nozzles and dotted lines? Are these problems related to pigment clogging, dried inks or rather air in the system, probably due to incorrect shaking of the cartridges or pigment settling on the system?

  • Can the “dotted lines in the nozzle check” be the cause of the banding I have seen when printing some negatives? (banding along the head printing direction)

  • What should be done to eliminate this problem, if air is the culprit? Printing a lot until all the ink stored between the carts and the head is released? Leaving the printer sit for a while? I am using a 9900… should I perform power cleanings, init fills, use piezoflush? Again, none of the nozzles performing weird seem to be stable within two consecutive nozzle tests…

Thanks so much in advance!


This has been covered on this forum several times, but I think this is actually a problem with your flush box and wiper bade. In short, I think you most likely have residue/gunk on your cleaning assembly and wiper. This is causing random nozzle outages after a clean.